Apparatus and method for wear detection of railroad vehicle wheels

ABSTRACT

A railroad wheel impact load detection test panel includes a secondary instrumentation rail proximate a field side of a primary or running rail of a section of railroad track, and elevated a prescribed distance so that the wheels of a rail car traverse the instrumentation rail within the test panel. The instrumentation rail includes an optical strain gauge to sense the wheel impact load. The sensed impact data is correlated with wheel damage signatures to identify wheels to be restored or replaced before failure occurs.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 17/009,297, filed Sep. 1, 2020, the entirety of which is herebyincorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure concerns the safety of railroad rolling stock andmore particularly the detection of defects on the tread surface ofwheels of railroad vehicles that occur due to, over-loading, thermaleffects, debris and foreign objects, sudden braking, and the like.

BACKGROUND

Railroad rolling stock—railroad cars and locomotives—are supported byand roll along a pair of parallel rails on steel wheels. Each wheelincludes a flange integral with the inside edge of the wheel. Theflange, of larger diameter than the running circumference of the wheel,extends downward next to the inside edge of its proximate rail. Thewheel treads are tapered to maintain wheel to rail contact. Thus, thewheel flanges on both sides of the car or locomotive can assist in thealignment of the wheels, and the car or locomotive, with the railroadtrack, on both straight and curved roadways. The wheels are subject toheavy loads, bearing most of the weight on the running surface or treadof the wheel between the flange and the outermost side—the “field”side—of the wheel.

Because of the very heavy loads carried by the rolling stock, the wheelsare subject to wear and damage. Various kinds of wear include abrasionsand indentations, surface and subsurface fatigue, cracks due to thermalor impact damage, flat spots, and wear due to sliding friction as thewheel moves sideways from motion of the car around curves or due tovibration and the like. Such damage to the wheels, if left undetectedcan lead to wheel failure, broken wheels, failure of thewheel-supporting structure called a “truck,” and, in the worst instance,derailment of the railroad vehicle. Occasionally, derailments can occurdue to in-service wheel failures, sometimes catastrophic in nature,which can result in high economic loss to the rolling stock and itscontents, serious damage to the property where the derailment occurred.The consequences of railroad derailment are severe.

The standard test protocol for measuring wheel defects such as abnormalwear, cracks, or broken wheels is called Wheel Impact Load Detection or“WILD.” Conventional WILD processes include various methods of detectingdamage and wear during operation of the rolling stock. One type measuresthe load on the running rails aligned with the tread surface of therail. Another type uses cameras to obtain visual images of potentialdefects for later inspection. A third type uses accelerometers tomeasure vibration associated with cracked wheels. These systems arecharacterized by limitations in their ability to detect and measure bothsurface and subsurface defects, by the complexity of using andinterpreting the measurements, by high false readings, either negativeor positive, and an inability to reliably detect potentially dangerousdefects.

Railroad train derailments caused by broken wheels are among the mostcatastrophic, from an equipment cause standpoint, and costly accidentsinvolving trains. As an illustration of these shortcomings, a recentindustry study found that more than 70% of broken wheels on freight carscontained defects that were not detected by the WILD methods before thewheels failed, on freight car wheel loads up to 80 kips. 80 kips isequal to 80,000 lb. of force. Moreover, the conventional WILD methods donot measure the impact loads in the region of the wheel tread surfacewhere most of the defects that cause failure occur—that portion of thewheel tread surface away from the flange and near the field side of thetread.

What is needed to overcome these deficiencies is a method of testingrailroad car and locomotive wheels that detects and isolates wheeldefects under heavy loads before such defect seriously degrades thewheel's ability to safely bear the loading it is subject to.

SUMMARY

In one embodiment the present disclosure, a railroad wheel impact loaddetection test panel can comprise a section of a railroad track havingfirst and second primary rails; a first secondary rail and a secondsecondary rail, each having a first end and a second end and disposedproximate a field side of each primary rail of the railroad track suchthat its running surface is elevated by a predetermined incrementrelative to the running surface of the primary rail; and a sensordisposed on the bottom surface of each secondary rail at a predeterminedlocation; wherein the secondary rail includes an elevation transitionramp disposed at each first and second end thereof.

In one aspect, each first and second secondary rail can comprise apredetermined length of rail supported proximate each primary rail suchthat its running surface is disposed by an elevation of 0.250 to 0.500inches above the elevation of the proximate primary rail; and each firstand second end of each secondary rail is tapered downward such that theelevation at each first and second end thereof is equal to the elevationof the proximate primary rail; wherein the predetermined length of thefirst and second secondary rails is at least 80 feet, the elevationtransition ramp has a slope within one part in twenty to one part in twohundred, and the elevation of each secondary rail is approximately 0.375inch.

In another aspect, the sensor can comprise an optical strain gaugehaving a fiber optic sensing element housed in a weather-resistantcontainer, strain gauges welded to the rail, load cells, load sensors,or other suitable sensor; and an integral connector for coupling theoptical strain gauge to external instrumentation; wherein the sensingelement has a sensitivity corresponding to a resolution of no greaterthan a one thousand pound (one kip) load on the first and secondsecondary rails. The external instrumentation comprises a housingsupported on a tower along a wayside of the railroad track; a processingsystem enclosed in the housing and connected through a cable to theintegral connector; wherein the processing system is controlled byprogram software stored in non-volatile memory coupled to the processingsystem.

In another aspect, the sensor can provide an output comprising adistinctive signature of wheel tread defects indicating one or more ofrim breakage, surface or subsurface fatigue, tread cracks, wheel flats,tread indentations, and sliding wear.

In another embodiment, a railroad wheel impact load detection test panelcan comprise a section of a railroad track having first and secondprimary rails; at least one secondary rail, having a first end and asecond end and disposed proximate a field side of either primary rail ofthe railroad track such that its running surface is elevated by apredetermined increment relative to the running surface of the primaryrail; and a sensor disposed on the bottom surface of the at least onesecondary rail at a predetermined location; wherein the at least onesecondary rail includes an elevation transition ramp disposed at eachfirst and second end thereof.

In one aspect, the at least one secondary rail can comprise apredetermined length of rail supported proximate each primary rail suchthat its running surface is disposed by an elevation of 0.250 to 0.500inches above the elevation of the proximate primary rail; and each firstand second end of the at least one secondary rail is tapered downwardsuch that the elevation at each first and second end thereof is equal tothe elevation of the proximate primary rail; wherein the predeterminedlength of the at least one secondary rail is at least 80 feet, theelevation transition ramp has a slope within one part in twenty to onepart in two hundred, and the elevation of each secondary rail isapproximately 0.375 inch.

In another aspect, the load sensor can comprise an optical strain gaugehaving a fiber optic sensing element housed in a weather-resistantcontainer; and an integral connector for coupling the optical straingauge to external instrumentation; wherein the sensing element has asensitivity corresponding to a resolution of no greater than a onethousand pound (one kip) load on the at least one secondary rail. Theexternal instrumentation comprises a housing supported on a tower alonga wayside of the railroad track; a processing system enclosed in thehousing and connected through a cable to the integral connector; whereinthe processing system is controlled by program software stored innon-volatile memory coupled to the processing system.

In another aspect, the load sensor can provide an output comprising adistinctive signature of wheel tread defects indicating one or more ofrim breakage, surface or subsurface fatigue, tread cracks, wheel flats,tread indentations, and sliding wear. In another exemplary embodiment,the wheels' condition can be based on individual wheel measures, theirside to side delta and that delta's magnitude, in terms of it being anoutlier in the train.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an end view of a railroad track test panel, in accordance withone or more exemplary embodiments of the present disclosure;

FIG. 2 is a plan view diagram of the test panel of FIG. 1 , inaccordance with one or more exemplary embodiments of the presentdisclosure;

FIG. 3 is an end view detail of a cross section of an instrument rail ofthe test panel of FIG. 1 , in accordance with one or more exemplaryembodiments of the present disclosure;

FIG. 4A is a perspective view of the sensor instrumentation installed atthe test panel of FIG. 1 , in accordance with one or more exemplaryembodiments of the present disclosure;

FIG. 4B is a close up perspective view of the sensor instrumentationinstalled at the test panel of FIG. 1 , in accordance with one or moreexemplary embodiments of the present disclosure;

FIG. 4C is a plan view of the sensor installed beneath an instrumentrail at the test panel of FIG. 1 , in accordance with one or moreexemplary embodiments of the present disclosure;

FIG. 5 is a diagram of surface zones of a railroad wheel subject tomeasurement at a test panel, in accordance with one or more exemplaryembodiments of the present disclosure;

FIG. 6 is a cross section diagram of a railroad wheel and the test railsof the test panel of FIG. 1 , in accordance with one or more exemplaryembodiments of the present disclosure; and

FIG. 7A is an illustration of a first example of wheel damage subject todetection by the test panel of FIG. 1 , in accordance with one or moreexemplary embodiments of the present disclosure;

FIG. 7B is an illustration of a second example of wheel damage subjectto detection by the test panel of FIG. 1 , in accordance with one ormore exemplary embodiments of the present disclosure;

FIG. 7C is an illustration of a third example of wheel damage subject todetection by the test panel of FIG. 1 , in accordance with one or moreexemplary embodiments of the present disclosure;

FIG. 7D is an illustration of a fourth example of wheel damage subjectto detection by the test panel of FIG. 1 , in accordance with one ormore exemplary embodiments of the present disclosure;

FIG. 7E is an illustration of a fifth example of wheel damage subject todetection by the test panel of FIG. 1 , in accordance with one or moreexemplary embodiments of the present disclosure; and

FIG. 7F is an illustration of a sixth example of wheel damage subject todetection by the test panel of FIG. 1 , in accordance with one or moreexemplary embodiments of the present disclosure.

DETAILED DESCRIPTION

Accordingly there is disclosed herein an advancement in the state of theart for detecting broken wheels and other wheel defects of railroadrolling stock using a modified track panel—a section of railroad trackconfigured as a test panel. The railroad track, as is well-known,includes a pair of parallel primary rails, usually fabricated of steeland spaced a prescribed gauge distance apart, and supported on a ballaststructure constructed on the Earth's surface. The ballast structure mayinclude, for example a continuous series of elongated, closely-spacedties—members disposed under and perpendicular to the first and secondrails—spaced at uniform intervals and supported on a composition bed ofstone or rock aggregate disposed along the railroad right of way. Theaggregate may be overlayed on a subgrade formed to support the heavyloads of a railroad train.

According to the present disclosure, a railroad wheel impact loaddetection (“WILD”) test panel includes a secondary instrumentation railproximate a field side of a primary or running rail of a section ofrailroad track, and elevated a prescribed distance so that the wheels ofa rail car traverse the instrumentation rail within the test panel. Theinstrumentation rail includes an optical strain gauge to sense the wheelimpact load. The sensed impact data is correlated with wheel damagesignatures to identify wheels to be restored or replaced before failureoccurs.

Briefly stated, the disclosure provides for the construction of the testpanel on a selected portion of a railroad track disposed along arailroad right of way. To the selected portion of primary rails isadded, on the outside or field side of each primary rail, a secondaryinstrument rail proximate each primary rail. In one embodiment thelength of each secondary instrument rail may be a predetermined valuethat should exceed the length of the longest rail car that will betested on the test panel. The running surface of each secondary rail iselevated by a predetermined increment relative to the running surface ofthe primary rails, and the secondary rail includes an elevationtransition ramp disposed at each first and second end thereof. Asensitive, an optical strain gauge or other suitable sensor, such as afiber optic sensor can be attached to the underside of each secondary orinstrument rail, between the rail and the cross tie supporting theprimary and secondary rails. The sensitivity of the sensor should beable to resolve a wheel load increment of a one kip (one thousand pound)load.

The sensor can detects the edge of tread impact as the wheels of arailroad vehicle roll over the instrument rail of the test panel at aprescribed speed while bearing its rated load. The sensor can be fiberoptic, mechanical, electrical, electromechanical, or other suitablesensor type. The sensor and its associated instrumentation receives,interprets, and records the edge of wheel tread impact information toprovide the test data. The signals emitted by the sensor, as the railcar rolls along the test panel, are sensitive to the different kinds ofwear that railroad wheels develop. The wear patterns, as illustrated inFIGS. 7A-7F, produce distinctive signals that may be received in theinstrumentation modules 62, 64, 66, interpreted by the instrumentationin the substation 80, and collected to enable scheduling of requiredservice to the wheel sets identified by the test panel. The test panelmay be configured to measure the edge of tread impact on both left andright side wheels of a wheelset of a railroad car truck assembly.

The test data provided by the test panel may be correlated with theparticular vehicle and each particular wheel according to codedinformation, called the Automatic Equipment Identification (“AEI”). TheAEI information code is stated as a Railroad Reporting Mark attached toeach rail car. The mark includes a two-to-four letter code identifyingthe owner of the rail car and a numeric code that identifies the carnumber. The marks may be read by trackside AEI readers, typically usingan RFID technology as one example. In some systems the test data outputfrom the instrumentation can be transmitted to a remote location andobserved in real time.

A railroad wheel is generally cast or forged of steel, heat treated, andmachined on a lathe to a specified profile and dimensions. Some wheelsare fitted with steel tires that may be replaced to restore the treadportion of a wheel to specification. Each wheel includes an integralflange of a larger diameter than the rest of the wheel. The flange isdisposed on the inside surface of the wheel to keep the wheel alignedwith the rail. A wheelset is formed by attaching a wheel on each end ofan axle, with the flanged sides facing each other. The wheelset issupported in a truck, an assembly of two wheelsets. The truck is mountedto the underside of a railway car so that it may pivot as the car roundsa curved track.

FIG. 1 is an end view of a railroad track test panel 10, in accordancewith one or more exemplary embodiments of the present disclosure. FIG. 2is a plan view diagram of the test panel of FIG. 1 and depicts the samestructural features shown in FIG. 1 .

The track test panel 10 (also called a track panel or a test panel 10herein), shown in a plan view in FIG. 2 , includes a pair of parallelprimary or running rails 12, a guard rail 14 disposed proximate theinside edge 16 of each primary rail 12, and a secondary instrument rail16 disposed closely proximate the outer “field” side of each primaryrail 12. The primary rails 12, sometimes called the traffic rails, arethe rails that support the train as it rolls along the railway. Therails are supported on ties 18, arranged perpendicular to the rails 12,14, 16 and spaced at uniform intervals from each other. The ties 18 arepreferably supported on a roadbed or ballast 20. The guard rails 14 andthe instrument rails 16 are rail segments that extend along the trackpanel for a distance exceeding the length of the railroad vehicle suchas a freight car. A typical freight car is 50 feet to 90 feet long,depending on the type of car (e.g., box car, flat bed car, hopper car,etc.), so the guard rails and instrument rails should exceed thatlength.

The guard rails 14 are tapered at each end 22 such that the gap 24between the guard rail 14 and the proximate primary rail 12 increasesaccording to a flare or taper specification expressed as a ratio: 1:D,where D=the length of the tapered section. Thus a taper or other angleof 1:20 describes an angle formed by an ordinate (Y axis) of 1 foot andan abscissa (X axis) of 20 feet. The taper 22 is provided to spread thegap 24 between the guard rail 14 and the primary rail 12 at the ends ofthe track panel 10 to facilitate alignment of the wheelsets of a railwaycar as it enters the track panel. The guard rails 14 serve to maintainthe flange of the wheels (not shown in this view) in a properrelationship with the instrument rail 16 to ensure repeatability of thesensed impact load measurements made while the test vehicle is rollingon the track panel 10. See FIG. 6 to be described for a cross sectionview of a wheel disposed on the rails of the track panel 10.

The instrument rails 16 are disposed in close proximity to the fieldside of the primary rail 12 and elevated by a small prescribed amount aswill be described. The instrument rail 16 is elevated slightly relativeto the primary rail 12 so that the outer portion of the wheel rollsalong the instrument rail 16 instead of the primary rail 12. The smallprescribed amount of elevation of the instrument rail may be within therange of 0.250 to 0.500 inches, and preferably 0.375 inch. An elevationtransition ramp having a slope within one part in twenty to one part intwo hundred is provided to enable a smooth transition of the wheel setsof a railway car as it rolls up to and down from the elevation of theinstrument rails 16, i.e., onto and of off the test panel 10. The solepurpose of the instrument rail 16 is to sense the impact load of thewheels as they roll along the rail. The instrument rail 16 is so calledbecause it includes a sensor (to be described) that measures the impactcaused by variations in the surface of the wheel tread.

FIG. 3 is an end view detail of a cross section of an instrument rail 16of the test panel 10 of FIG. 1 , in accordance with one or moreexemplary embodiments of the present disclosure. The instrument rail 16is also shown in FIG. 6 as instrument rail 182. The instrument rail 182includes a running surface 36 and an underside surface 38. Attached tothe underside 38 of the instrument rail 182 is an optical strain gaugesuch as a fiber optic sensor 184. The fiber optic sensor 184 is attachedto the underside surface 38 of the instrument rail 182 using a clamp 42secured by a bolt 44 to each edge of the rail 182. The operation of thesensor 184 is described further in FIG. 6 .

FIGS. 4A through 4C depict views of the instrumentation portions of thetrack panel 10 in a railroad yard setting.

FIG. 4A is a perspective view of the wayside 50 that includes the sensorinstrumentation installed at the test panel 10 of FIG. 1 , in accordancewith one or more exemplary embodiments of the present disclosure. Theinstrumentation at the wayside 50 includes three towers 52, 54, and 56spaced a prescribed distance from the test panel 10. Each tower 52, 54,and 56 provides support for respective instrument modules 62, 64, and66. A cable is connected from each fiber optic sensor 184 (not shown inthe view in FIG. 4A) attached to an instrument rail 182 in the testpanel 10 to a respective instrument module 62, 64, and 66. The cables72, 74, and 76 conduct the detected impact load signals from a fiberoptic sensor 182 to instrumentation circuits within the instrumentmodules 52, 54, and 56. The wayside 50, includes a substation 80, whichmay be housed in an enclosed structure. The substation may receive dataprocessed in the instrument modules 62, 64, 66 for analysis and formatthe data for communication to a central location such as a railyardcontrol facility (not shown). The communication from the Instrumentmodules 62, 64, and 66 to the substation 80 may be through a wired orwireless RF transmission. Similarly, the substation 80 may transmit theresults of its analysis operations wirelessly to the railyard controlfacility.

FIG. 4B is a close up perspective view of the sensor instrumentationinstalled at the test panel 10 at the wayside 50 of FIG. 4A, inaccordance with one or more exemplary embodiments of the presentdisclosure. In the depicted section 90 of the wayside 50 are the runningrail 12, the guard rail 14 and the instrument rail 16 of the near sideof the railway test panel 10. Also shown are the instrumentationcomponents for one of the fiber optic sensors including a tower 52, aninstrumentation module 62, and a pair of cables 72, one connected to afiber optic sensor attached to the underside of both instrument rails(left and right, on the near 72A and far 72B sides of the railway) ofthe test panel 10. In the illustrated example, the instrumentationmodule 62 may include a housing 68 (FIGS. 4A, 4B) that contains aprocessing system (not shown) which may be operated according to programsoftware stored in a non-volatile memory coupled to the processingsystem. The processing system is coupled through the cables 72A and 72Bto the fiber optic sensor 184 (FIGS. 3, 4A, 4B and 6 ) at the integralconnector 70 (FIG. 3 ). The housing may be supported on a tower 52 alongthe wayside 50 of the railroad track. Also shown in FIG. 4B is acanister that may be configured as a removable data device, a dataprocessing module, or a wireless transmitter/receiver, and the like.

FIG. 4C is a close-up plan view 100 of an installation of one sensor 184(not visible in the figure, but refer to FIG. 3 ) installed beneath aninstrument rail 16 at the test panel 10 of FIG. 4A, in accordance withone or more exemplary embodiments of the present disclosure. This viewincludes the running rail 12, the guard rail 14, and the instrument rail16. On the instrument rail 16 is shown the surface 36 upon which arailroad wheel 160 rolls during a wheel impact load test event to detectconditions of wear on the wheel 160. The shaded area in FIG. 4C depictssurface wear on the instrument rail 16. The fiber optic sensor issecured by the bolts 42.

FIG. 5 is a cross section diagram of surface zones of a railroad wheel160 of a wheelset. Wear patterns of the wheel 160 (See FIGS. 7A through7F following) are subject to measurement at the test panel 10, inaccordance with one or more exemplary embodiments of the presentdisclosure. The wheel 160 includes a field side 162 and a flange 164 onthe opposite side of the wheel 160. The tread surface 166 of the wheelis marked in defined zones of wear as follows. Zone 1 (168) is the fieldside, and zone 2 (170) is the root zone, adjacent to the flange 164.Zone 3 (172) and zone 4 (174), which form the locus of wear of the wheelon a rail under normal conditions, straddle the tape line 176—acenterline of the wheel tread 166—typically to a width of approximately½ inch either side of the tape line 176.

FIG. 6 is a cross section diagram of a railroad wheel 160 and the testrails of the test panel 10 of FIG. 1 . A ballast 20 provides support forthe test rails of the track panel 10. As is well known in the art theballast may include several layers of built-up material such as crushedrock, and the like to provide a firm, stable foundation for cross ties18 (not shown in FIG. 6 but see, e.g., FIG. 1 ) that in turn support thetest rails. In FIG. 6 the test rails include a primary rail 180 disposedbetween a secondary rail 182 and a guard rail 188. The primary rail 180(No. 12 in FIG. 1 ) is also called the running rail the train normallyrides on. The secondary (testing) rail can be milled to a ½″ depth,while the running rail can be machined to ⅜″ in depth, such that theoutside rail can ramp up (moving left to right) as the running railramps down, causing the ramps to intersect to create a smoothtransition. As shown in FIG. 5 , the wear zones of the wheel tread 166are marked with the numerals 1, 2, 3, and 4.

The secondary rail 182 (No. 116 in FIG. 1 ) is also called theinstrument rail 182 of the track panel 10. The guard rail 188 (No. 14 inFIG. 1 ), is spaced away from the primary rail 180 to provide clearancefor the flange 164 to maintain the alignment of the wheel 160 with theprimary rail 180. A guard rail 188 (14 in FIG. 1 ) is spaced away fromthe inside edge of both primary rails 180 (12 in FIG. 1 ). The secondaryrail 182 is spaced in close proximity to the primary rail and elevatedby a prescribed distance—an elevation increment 190—above the primaryrail 180. The elevation increment is provided to elevate the surface ofthe secondary (instrument) rail 182 just enough to ensure that the wheel160 being tested is supported by the secondary rail 182 instead of theprimary rail 180.

Experimental results indicate that an elevation increment of 0.375 inchis a satisfactory value that allows a sufficient amplitude range toaccommodate most wheel defects while holding the elevation increment toa minimum practical value. The elevation increment 190 is preferablyreduced gradually toward each end of the secondary rail 182 to provide asmooth transition of the wheel from the primary rail 180 to thesecondary rail 182. Also shown in FIG. 6 is the slope or taper formed inthe wheel tread 166 set to a 1:20 ratio. The taper is a normalconfiguration of a railroad wheel that is provided to enable the wheelset to self-steer when going through curved sections of track. Theprimary rail 180 may have a similar taper or slope to facilitate theself-steering.

Continuing with FIG. 6 , the instrument rail 182 includes a sensor 184attached to the underside of the instrument rail 182 within a clearancespace 186 between the instrument rail 182 and the ballast 20. Thepreferred sensor 184 is a fiber optic element configured as a straingauge attached to the underside of the instrument rail 182. The fiberoptic element in the load sensor 184 can be sensitive to minutedisplacements of the instrument rail 182 when deflected by a railcarrolling over it. An advantage of fiber optic sensors is that they areimmune from effects of electric or electromagnetic fields orinterference. The operating principle of a fiberoptic strain gauge isthat the optical fiber, which has a Bragg grating structure formed in asegment of the fiber, can be configured to alter the character of alaser light signal traveling in the fiber in proportion to the strainwhen the fiber optic element is bent due to the load as a railcar wheelrolls along the instrument rail 182. A portion of the light signal maybe reflected while a second portion may be transmitted. Thus, theresulting output is a modulated optical signal whose characteristics canbe correlated with the differing signatures of various wear patterns,thereby detecting defective and broken wheels.

FIGS. 7A through 7F depict examples of the kinds of defects that mayoccur in the treads of railway wheels. Each type of defect may bedistinguished by their characteristic or distinctive signature, whichmay be correlated with the wheel impact load data produced by the testpanel described herein. Specifically, the output of the sensors attachedto the underside of the instrument rails 16 may be correlated with theimpact sensed by the fiber optic sensor to provide data regarding theroadworthiness of each wheel of a railway car. The data can be used toenable identification of wheel load impact defects before they mightmature sufficiently to cause an accident or derailment. Examples ofwheel defects that may be detected include rim breakage, surface orsubsurface fatigue, tread cracks, wheel flats, tread indentations, andsliding wear.

FIG. 7A is an illustration of a severe example of wheel damage to theouter edge—zone 1—of a wheel tread that may be the result of cracks orfractures in the wheel tread. This exemplary kind of damage can bedetected by the test panel of FIG. 1 . In FIG. 7A a substantial amountof the wheel tread surface has broken away, revealing serious subsurfacedamage to the wheel tread. Such damage tends to occur in zone 1 becausethe wheel tread thickness is at a minimum in that region. A wheel withthat degree of damage must be replaced immediately because a fracture islikely imminent.

FIG. 7B is an illustration of a second example of wheel damage that maybe detected by the test panel of FIG. 1 . The depicted damage is a shortbut mature crack to the outer edge 162 (zone 1) of the wheel tread 166that leaves the wheel tread very vulnerable to further breakdown of theedge of the wheel tread 166, such as depicted in FIG. 7A, and possiblewheel fracture.

FIG. 7C is an illustration of a third example of wheel damage subject todetection by the test panel of FIG. 1 . This damage is similar to FIG.7B except that the damage is confined to the surface of the edge portionof zone 1 of the wheel tread 166. Regardless, the wheel set—the assemblyof the left and right wheels and the axle connecting them—should beremoved so that the wheel tread of the damaged wheel 160 can berestored.

FIG. 7D is an illustration of a fourth example of wheel damage subjectto detection by the test panel of FIG. 1 . The surface of the wheeltread 166 in zones 2 and 3 is pock-marked due to gravel or other foreignmatter caught between the wheel tread 166 and the rail (See rail 12, inFIG. 1 ) while carrying a load. Also visible is evidence of minorpitting or indentations depicted by the smaller impressions representedby random dots. This type of damage, as long as it is not accompanied byevidence of cracks, is usually benign.

FIG. 7E is an illustration of a fifth example of wheel damage subject todetection by the test panel of FIG. 1 . The well-defined cracks in thewheel tread as shown in this figure are the result of heating due tobraking followed by rapid cooling. The heating/cooling cycle causessurface tensile stresses that may extend deep into the subsurface of thewheel tread, producing a martensite transformation, leading to thecondition generally known as spalling. Spalling appears as fractures inthe running surfaces of the wheel tread or flange due to surface orsubsurface fatigue brought on by a braked railroad wheel under heavyload sliding along a rail. Such fatigue, through the martensitictransformation leads to cracks, as shown in FIG. 7E, as well as flaking,pitting, or peeling of the surface material of the wheel 160.

FIG. 7F is an illustration of a sixth example of wheel damage subject todetection by the test panel of FIG. 1 . This type of damage, thatappears as a rectangular pattern on the surface of the wheel tread 166in zones 2 and 3 is typical of a flat spot caused by a sliding wheel 160locked by brake action. The sliding action may also result in thermaldamage from the sliding friction between the wheel tread 166 and therail (See rail 12 in FIG. 1 ). Thermal damage, as discussed above, canresult in a martensitic transformation, and which may, in severe cases,cause a loosening of the bond between the wheel tread 166 and its wheel160.

Briefly stated, the disclosure teaches a railroad wheel impact loaddetection panel, installed along section of a railroad track havingfirst and second primary rails; a second length of a secondary railhaving a first end and a second end disposed proximate the field side ofeach primary rail of the railroad track such that its running surface iselevated by a predetermined increment relative to the running surface ofthe primary rail; and a sensor disposed on the bottom surface of eachsecondary rail at a predetermined location; wherein the secondary railincludes an elevation transition ramp disposed at each first and secondend thereof.

In operation, the test panel 10, which may be situated at a waysidealong a railway at designated locations such as nearby monitoring orcontrol stations, provides a convenient, automated way to detect wheeldamage to rolling stock wheel sets requiring service, restoration, orreplacement. The test panel instrumentation measures and interprets theimpact loading signals emitted by the sensor attached to the undersideof the secondary instrumentation rail 16 disposed alongside the runningrail 12. The instrumentation rail 16 is positioned slightly above therunning surface of the running rail 12 to bear the load of a passingrail car as it rolls over the test panel 10. A transition region isprovided at each end of the test panel 10 to ramp upward and downwardrespectively thereby enabling the rail car to smoothly enter and departthe test panel 10.

The signals emitted by the sensor, as the rail car rolls along the testpanel, are sensitive to the different kinds of wear that railroad wheelsdevelop. The wear patterns, as illustrated in FIGS. 7A-7F, producedistinctive signals or signatures that may be received in theinstrumentation modules 62, 64, 66, and interpreted by theinstrumentation in the substation 80, and collected to enable schedulingof required service to the wheel sets identified by the test panel 10.The test panel 10 is configured to detect wheel damage that occurs inboth the wheel tread (zones 3 and 4 in FIG. 6 ) and the outer (fieldside) edge 162 of the wheel (zone 1 in FIG. 6 ). As configured, the testpanel 10 is particularly effective in detecting zone 1 damage, where themost severe damage is likely to occur.

While the disclosure may have been shown in only one of its forms, it isnot limited to that one form but is susceptible to various changes andmodifications without departing from the concepts and principles setforth in the enumerated claims. For example, while the embodimentsdescribed herein illustrate one combination of structural elements,other equivalent combinations are contemplated within the scope of theclaims. Alternative structural features may include different types ofstrain gauges that satisfy the sensitivity requirements. The dimensionsof the track test panel such as the spacing of rails, elevation, taper,and transition slope are permitted as long as the combination serves thepurposes of the track test panel. The specific form of theinstrumentation, including computer processing elements and theassociated software, data correlations, and algorithms needed for theiroperation is understood to be adapted to the particular circumstances ofthe railroad wheel impact load detection protocols.

Persons skilled in the art will readily understand that these advantages(as well as the advantages indicated in the summary) and objectives ofthis system would not be possible without the particular combination ofcomputer hardware, control logic, and other structural components andmechanisms assembled in this inventive system and described herein. Itwill be further understood that a variety of programming tools, known topersons skilled in the art, are available for implementing the controlof the features and operations described in the foregoing disclosure.Moreover, the particular choice of programming tool(s) may be governedby the specific objectives and constraints placed on the implementationselected for realizing the concepts set forth herein and in the appendedclaims.

The description in this patent document should not be read as implyingthat any particular element, step, or function can be an essential orcritical element that must be included in the claim scope. Also, none ofthe claims can be intended to invoke 35 U.S.C. § 112(f) with respect toany of the appended claims or claim elements unless the exact words“means for” or “step for” are explicitly used in the particular claim,followed by a participle phrase identifying a function. Use of termssuch as (but not limited to) “mechanism,” “module,” “device,” “unit,”“component,” “element,” “member,” “apparatus,” “machine,” “system,”“processor,” “processing device,” or “controller” within a claim can beunderstood and intended to refer to structures known to those skilled inthe relevant art, as further modified or enhanced by the features of theclaims themselves, and can be not intended to invoke 35 U.S.C. § 112(f).

The disclosure may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. For example, eachof the new structures described herein, may be modified to suitparticular local variations or requirements while retaining their basicconfigurations or structural relationships with each other or whileperforming the same or similar functions described herein. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive. Accordingly, the scope of the presentdisclosure should be established by the appended claims rather than bythe foregoing description. All changes which come within the meaning andrange of equivalency of the claims are therefore intended to be embracedtherein. Further, the individual elements of the claims are notwell-understood, routine, or conventional. Instead, the claims aredirected to the unconventional inventive concept described in thespecification.

What is claimed is:
 1. A railroad wheel impact load detection system, comprising: a section of a railroad track having first and second primary rails; at least one secondary rail, having a first end and a second end and disposed proximate a field side of either primary rail of the railroad track such that its running surface is elevated by a predetermined increment relative to the running surface of the primary rail; and a sensor disposed on the bottom surface of the at least one secondary rail at a predetermined location, wherein the at least one secondary rail includes an elevation transition ramp disposed at each first and second end thereof, and wherein the at least one secondary rail includes a first secondary rail and a second secondary rail, each having a first end and a second end and disposed proximate a field side of a corresponding primary rail of the first and second primary rails.
 2. The system of claim 1, wherein: the first and second primary rails are spaced a defined gauge distance apart and supported on a ballast composition, wherein the section of railroad track is a selected portion of track disposed on a railroad right of way.
 3. The system of claim 1, wherein each of the at least one secondary rail comprises: a predetermined length of rail supported proximate each primary rail such that its running surface is disposed by an elevation of 0.250 to 0.500 inches above the elevation of the proximate primary rail; and each first and second end of each of the at least one secondary rail is tapered downward such that the elevation at each first and second end thereof is equal to the elevation of the proximate primary rail, wherein the predetermined length of each of the at least one second secondary rails is at least 80 feet.
 4. The system of claim 3, wherein the elevation of each of the at least one secondary rail is 0.375 inch above the elevation of the proximate primary rail.
 5. The system of claim 1, wherein the elevation transition ramp has a slope within one part in twenty to one part in two hundred.
 6. The system of claim 1, wherein the sensor comprises: an optical strain gauge having a fiber optic sensing element housed in a weather-resistant container; and an integral connector for coupling the optical strain gauge to external instrumentation, wherein the sensing element has a sensitivity corresponding to a resolution of no greater than a one thousand pound (one kip) load on the at least one second secondary rail.
 7. The system of claim 6, wherein the external instrumentation comprises: a housing supported on a tower along a wayside of the railroad track; and a processing system housed in the housing and connected through a cable to the integral connector, wherein the processing system is controlled by program software stored in non-volatile memory coupled to the processing system.
 8. The system of claim 1, wherein further comprising: a first and second guard rail disposed along each primary rail and spaced a defined distance inward from each primary rail, wherein the defined distance is sufficient to allow free passage of a standard railroad wheel flange.
 9. The system of claim 1, wherein the sensor provides an output comprising: a signature of wheel tread defects indicating one or more of rim breakage, surface or subsurface fatigue, tread cracks, wheel flats, tread indentations, and sliding wear.
 10. The system of claim 9, further comprising a test panel configured to detect wheel damage that occurs in both the wheel tread and the outer edge of the wheel using the signature.
 11. A method for detecting rail vehicle wheel impact, comprising: traversing a section of a railroad track having first and second primary rails, and at least one secondary rail, having a first end and a second end and disposed proximate a field side of either primary rail of the railroad track such that its running surface is elevated by a predetermined increment relative to the running surface of the primary rail; detecting the edge of tread impact as the wheels of a railroad vehicle roll over the at least one secondary rail of the test panel at a prescribed speed while bearing its rated load via a sensor disposed on the bottom surface of the at least one secondary rail at a predetermined location; and detecting wheel damage that occurs in both the wheel tread and the outer edge of the wheel using a signal received from the sensor, wherein the at least one secondary rail includes a first secondary rail and a second secondary rail, each having a first end and a second end and disposed proximate a field side of a corresponding primary rail of the first and second primary rails.
 12. The system of claim 1, wherein: the first and second primary rails are spaced a defined gauge distance apart and supported on a ballast composition, wherein the section of railroad track is a selected portion of track disposed on a railroad right of way.
 13. The method of claim 11, wherein each of the at least one secondary rail comprises: a predetermined length of rail supported proximate each primary rail such that its running surface is disposed by an elevation of 0.250 to 0.500 inches above the elevation of the proximate primary rail; and each first and second end of each of the at least one secondary rail is tapered downward such that the elevation at each first and second end thereof is equal to the elevation of the proximate primary rail, wherein the predetermined length of each of the at least one second secondary rails is at least 80 feet.
 14. The method of claim 13, wherein the elevation of each of the at least one secondary rail is 0.375 inch above the elevation of the proximate primary rail.
 15. The method of claim 11, wherein the elevation transition ramp has a slope within one part in twenty to one part in two hundred.
 16. The method of claim 11, wherein the sensor comprises: an optical strain gauge having a fiber optic sensing element housed in a weather-resistant container; and an integral connector for coupling the optical strain gauge to external instrumentation, wherein the sensing element has a sensitivity corresponding to a resolution of no greater than a one thousand pound (one kip) load on the at least one second secondary rail.
 17. The method of claim 16, wherein the external instrumentation comprises: a housing supported on a tower along a wayside of the railroad track; and a processing system housed in the housing and connected through a cable to the integral connector, wherein the processing system is controlled by program software stored in non-volatile memory coupled to the processing system.
 18. The method of claim 11, further comprising: a first and second guard rail disposed along each primary rail and spaced a defined distance inward from each primary rail, wherein the defined distance is sufficient to allow free passage of a standard railroad wheel flange.
 19. The method of claim 11, wherein the sensor provides an output comprising: a signature of wheel tread defects indicating one or more of rim breakage, surface or subsurface fatigue, tread cracks, wheel flats, tread indentations, and sliding wear.
 20. The method of claim 19, further comprising a test panel configured to detect wheel damage that occurs in both the wheel tread and the outer edge of the wheel using the signature. 